Industrial robots have become an indispensable part of modern manufacturing. Whether transferring semiconductor wafers from one process chamber to another in a cleanroom or cutting and welding steel on the floor of an automobile manufacturing plant, robots perform many manufacturing tasks tirelessly, in hostile environments, and with high precision and repeatability.
In many robotic manufacturing applications, it is cost-effective to utilize a relatively generic robot to accomplish a variety of tasks. For example, in an automotive manufacturing application, a robot may be utilized to cut, grind, or otherwise shape metal parts during one production run, and perform a variety of spot welding tasks in another. Different welding tool geometries may be advantageously mated to a particular robot to perform welding tasks at different locations or in different orientations. In these applications, a tool changer is used to mate different tools to the robot. One half of the tool changer, called the master module, is permanently affixed to a robot arm. The other half, called the tool module, is affixed to each tool that the robot may utilize. When the robot arm positions the master module adjacent the tool module connected to a desired tool, a coupler is actuated that mechanically locks the master and tool modules together, thus affixing the tool to the end of the robot arm. Tool changers and their constituent couplers are well known in the robotics arts, and are commercially available, such as from the assignee, ATI Industrial Automation of Apex, N.C.
In many robotic applications, it is advantageous to pass utilities—such as electrical current, air pressure, hydraulic fluid, cooling water, electronic or optical data signals, and the like—from the robot arm to an attached tool, and/or vice versa. To accommodate the wide variety of such utilities, a modular approach is known, whereby the two constituent halves of a utility-passing mechanism are removeably attached to the respective master and tool modules of a robotic tool changer. To facilitate a variety of such utility modules, the tool changer modules include one or more “shelves,” having a standardized shape and dimension, formed at the sides of each of the master and tool modules. Utility modules conforming to the mechanical standard may be attached as required. The modules include interface elements, such as electrical pin connections, self-sealing pneumatic valves, and the like, to pass utilities across the module interface when the two halves abut as the master and tool modules couple together.
One type of utility module commonly attached to robotic tool changers is a module to pass electrical power and/or electrical data signals. In particular, one known type of electrical connection comprises spring-loaded pins, which contact corresponding conductive plates when the modules halves abut. The springs biasing the pins forward ensure contact with the conductive plates. These modules rely on guide pins and corresponding receiving holes to precisely align the modules prior to the pins and plates making physical (and hence electrical) contact. However, in practice, the modules are often misaligned in any (or multiple) of several axes. This results in not all electrical contacts making electrical connection at the same time. Also, the exposed conductive plates (which are usually the “hot” side of the interface, at least for power delivery) are exposed, presenting both a shock hazard and a short circuit hazard.
The Background section of this document is provided to place embodiments of the present invention in technological and operational context, to assist those of skill in the art in understanding their scope and utility. Approaches descried in the Background section could be pursued, but are not necessarily approaches that have been previously conceived or pursued. Unless explicitly identified as such, no statement herein is admitted to be prior art merely by its inclusion in the Background section.